The invention discloses a composite reinforced corrosion-resistant high-temperature alloy and a preparation process thereof. The alloy comprises the following components of, by mass, 20%-24% of Cr, 10%-15% of Co, 1.5%-2.5% of Ti, 2.5%-3.5% of Al, 3%-7% of W, less than or equal to 0.5% of Si, less than or equal to 0.5% of Mn, 0.5%-1.5% of Nb, 0.03%-0.08% of C, 0.5%-1.0% of Fe and the balance Ni, wherein Al/Ti is greater than or equal to 1.5, and W + Cr is less than or equal to 27%. The preparation process of the alloy comprises the following steps that smelting is carried out; homogenizing is carried out; then hot rolling is carried out; and finally heat treatment is carried out. According to the composite reinforced corrosion-resistant high-temperature alloy and the preparation process thereof, the good strength performance of the alloy is obtained by promoting a large amount of secondary strengthening phases which are uniformly distributed inside the alloy in a dispersed mode to be separated out, meanwhile, solid solution strengthening elements with certain content are added on the premise that the stability of the alloy structure is ensured, and the excellent anti-oxidation and anti-corrosion performances of the alloy are guaranteed at the same time.